Ahmed, Sofia Bano

Purpose: Guidelines recommend serum estradiol concentrations of 100–200 pg/mL for transgender women prescribed oral, subcutaneous, or transdermal estradiol with or without adjunct antiandrogen as gender-affirming feminizing hormone therapy (HT). The purpose of this systematic review was to evaluate if the guideline range of 100–200 pg/mL for estradiol concentration is associated with indicators of adequate gender-affirming feminizing HT, specifically feminizing sufficiency, insufficiency, testosterone suppression, or toxicity in transgender women. Methods: The Populations/Intervention/Comparator/Outcome model was applied to the study question, whereby the target population included transgender, gender-diverse, and nonbinary adults using gender-affirming feminizing HT by any route of administration, with or without adjunct antiandrogen use. The comparator was defined as estradiol concentrations within (100–200 pg/mL or 367–734 pM) versus outside (</>100–200 pg/mL) the guideline range; evaluated outcomes were listed by the same clinical guidelines that recommend using the 100–200 pg/mL range. Embase, MEDLINE, and Web of Science were queried over a 24-year time frame (January 1, 1999–April 20, 2023); the search was restricted to English. The extracted outcomes were categorized as indicators of therapeutic insufficiency, sufficiency, toxicity, or hormone concentration. Results: There were 49 studies that met the inclusion criteria, of which 9, 42, 25, and 5 studies included indicators of therapeutic insufficiency, sufficiency, toxicity, or hormone concentration, respectively. The search did not identify articles demonstrating that the 100–200 pg/mL guideline range provides optimal feminizing outcomes or reduces adverse events. Conclusions : Evidence does not support using the guideline range of 100–200 pg/mL to indicate sufficient feminization in transgender women using gender-affirming feminizing HT.

Abstract Background There have been conflicting messages about the influence of female sex hormones on women's health, with historical messaging indicating that use of estrogen and/or progesterone in peri- or postmenopause poses a significant clinical risk to cisgender women. More recent guidance indicates that the benefit of hormone therapy (HT) outweighs the risks for symptomatic women. Exogenous estrogen use is also indicated for contraception and gender-affirming care. Despite the potential for broad applications, robust reference intervals for estradiol, progesterone, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are lacking, and guidelines indicate that measurement of 17-β-estradiol (E2), progesterone, LH, or FSH does not facilitate care in women who may be experiencing menopausal symptoms or women taking exogenous HT. Content Here we review the physiological roles of estrogen, progesterone, LH, and FSH. We examine the modes of administration for estrogen and progesterone, clarify the nomenclature related to exogenous hormone use, and comprehensively review the literature for studies evaluating normal concentrations of these female gonadal axis hormones during the menstrual cycle. The content primarily focuses on cisgender women, but some aspects of these hormones in transgender women will also be discussed. Summary Currently, E2, LH, FSH, and progesterone reference intervals for women remain incomplete. Although there are a variety of clinical indications that benefit women using HT, symptoms and shared decision-making should guide care. Collaborative efforts between clinicians and laboratory professionals to better define therapeutic or reference intervals for these hormones can advance women's health globally.